Textile process and device



8- I i T. D. BROWN 3,461,509

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United States Patent Olfice 3,461,509 Patented Aug. 19, 1969 3,461,509 TEXTILE PROCESS AND DEVICE Thomas Desmond Brown, Keighley, England, assignor to I.W.S. Nominee Company Limited, London, England Filed July 17, M67, Ser. No. 653,838

Claims priority, application Great Britain, July 22, 1966,

33,171/ 66 Int. Cl. D6112 3/04 US. C]. 19-66 13 Claims ABSTRACT OF THE DISCLOSURE Textile fibres are stretched by anchoring an assembly of such fibres, for example a sliver, to a carrier, across its width at a number of positions along its length, and while the assembly of fibres is being advanced by the carrier, stretching forces are applied between adjacent positions of anchorage, for example, by progressively moving the anchorage positions apart or by laterally displacing portions of the assembly of fibres between adjacent positions of anchorage. The process may be carried out in a device consisting essentially of a conveyor having gripping members spaced along its length and means for extending the length of the portions of the assembly of fibres held between adjacent gripping members, as the assembly of fibres is advanced by the conveyor. The length of such portions can be extended either by increasing the distance between adjacent gripping members as the conveyor moves or by bringing stretching members into engagement with the fibres between adjacent gripping members to displace and thereby stretch the fibres. The fibres can then be set in the stretched condition by appropriate techniques. The stretched and set fibres can be mixed with unstretched fibres in spinning, and the resulting yarn when relaxed, for example in hot water or aqueous solutions, then forms a bulked yarn.

This invention relates to a process and apparatus for stretching textile fibres. This process and apparatus are espefially suitable for fibrous keratinous material, such as woo Stretched fibres are used in the manufacture of socalled bulked textile materials, that is to say materials, for example yarns and fabrics, which have low density. In the manufacture of such materials, stretched fibres are mixed with unstretched fibres and the mixture is then subjected to conditions which causes the former to relax. When relaxation occurs the stretched fibres decrease in length and, since they are in frictional engagement with the unstretched fibres, the latter are contracted in length and become crinkled. Bulked textile materials are of considerable importance because they permit the manufacture of garments or other textile articles which are of light weight and have excellent heat insulating properties and attractive appearance. These materials also enable textile fibres to be used much more economically.

Processes are known for the stretching of conttinuous filament tow. These processes are, however, unsatisfactory for application to wool fibres because the latter are very short. Consequently the prior processes are inapplicable to stape fibres, e.g., wool fibres. A process has now been discovered which enables wool fibres, as well as other fibres, to be subjected to a high degree of stretching, whereby bulked textile materials can be obtained which have one or more of the properties mentioned above, in addition to good mechanical strength.

Accordingly, this invention comprises a process of stretching an assembly of textile fibres in which the assembly is first anchored across its width at a plurality of positions along its length to a carrier which advances the assembly and stretching forces are then applied to the assembly of fibres between adjacent positions of anchorage as the assembly is advanced. The effect of such forces is to increase the actual length of the fibre assembly held between such adjacent anchorage positions.

By the term fibre is herein meant either a continuous filament or a staple fibre. The process can be applied to either natural or synthetic fibres and these can be in the form of sliver, roving, tow, spun yarn or continuous filaments. The invention is, however, most advantageous in its application to natural or synthetic staple fibres and more especially to natural fibres such as cotton or wool.

Where the fibres require a setting treatment to preserve them in a stretched condition, this treatment can be given while the assembly in its stretched condition is still anchored to the carrier, which for this purpose can carry the assembly through a heated, steam-filled or other appropriate setting zone. Where it is necessary or desirable to give the fibres a preliminary treatment, to facilitate stretching or subsequent setting of the fibres, this treatment can be carried out either before the fibres reach the carrier or when the assembly has been anchored to the carrier.

The treatments required will vary with the fibre being handled. In the case of wool, the combined effect of steam and moisture are suflicient in both the preliminary and setting stages. In the case of synthetic polymeric fibres, these may be softened before stretching, either by heat or by an appropriate solvent. In either case, the treatment after stretching will comprise either cooling or the evaporation of solvent, and this can also take place, if desired, while the fibre assembly is on the carrier.

The invention also provides a device for stretching textile fibres by the process defined above.

Such a device comprises a conveyor provided with gripping members spaced along its length and adapted to anchor an assembly of textile fibres at corresponding positions to the conveyor, and means for extending the length of the portions of the assembly between adjacent gripping members as the conveyor advances the assembly.

According to one preferred form of such a device, means are provided for increasing the distance between adjacent gripping members in the direction of advance of the assembly as the assembly advances whereby the fibre assembly anchored thereto is extended.

According to a second preferred form of device, means are provided for laterally displacing the portions of the fibre assembly extending between adjacent gripping members whereby their respective lengths are increased.

The invention will now be further described, by way of example, with reference to the accompanying schematic drawings, which show two devices embodying the invention. In the drawings:

FIG. 1 is a vertical section through one form of stretching device according to the invention,

FIG. 2 is an end view of the stretching device illustrated in FIGURE 1, taken along the line II-II.

FIG. 3 is a side elevation of a second form of stretching device.

FIG. 4 is a side elevation of an enlargement of the stretching device illustrated in FIGURE 3, in the region FIG. 5 is a side elevation of a third form of stretching device.

FIG. 6 is a side elevation of an enlargement of the device illustrated in FIGURE 5, in the zone 14.

FIG. 7 is a graph showing percent openness factor against percent stretch fibre content in blends of stretched and unstretched fibres.

Referring now to FIGS. 1 and 2, the device shown therein includes a pair of variable pitch screw conveyors 10 and return screw conveyors 11 carrying upper and lower fallers 12 and 13 which cooperate to grip a sliver 14 of wool fibres supplied by feed rollers 15, driven by 3 belts 16 from rollers 17. At the discharge end of the device, the stretched sliver is withdrawn by take-01f rollers 18 and the fallers 12 and 13 are raised or lowered to their respective return screw conveyors for return to the feed end of the device.

The sliver 14 on entering the device passes first through zone A where the fibres are treated with steam. In this zone the grooves of the conveyor are closely spaced and equidistant from one another. In a second or stretching zone B, steam is also applied to the fibres. In this zone the grooves in the conveyor become progressively more widely spaced. In the following zone C more steam is applied to the fibres. In this zone the grooves in the conveyor are equidistant from one another and the distance by which they are spaced is equal to the maximum distance attained between the last two grooves in the conveyor in the stretching zone B. The zone C is followed by a zone D where the fibres are cooled. In this zone also the grooves are equidistant from one another.

As shown in greater detail in FIGURE 2 each pair of fallers 12 and 13 grip a number of slivers 14 of Wool. The upper faller 12 is urged against the slivers by loading springs 20 and associated longitudinal thrust strips and the lower faller is supported along its length by a number of thrust or backing strips 21.

In operation, a sliver of wool fibres is fed into the stretcher by means of the feed rollers 15. It is then gripped between opposing pairs of fallers 12 and 13. Each pair is equidistant from its neighbouring pairs in zone A where the fibres are heated with steam to render them stretchable. As the variable pitch screw conveyors rotate, the fallers 12 and 13 gripping the fibres advance them into the stretching zone B where grooves in the screw conveyors become progressively more widely spaced. As a consequence the distance between the fallers also increases, with the result that the fibers become stretched increasingly in their passage through the zone. In order to allow the fibres to adjust themselves to the effects of the stretching they are passed through the third zone C where they are maintained in their stretched condition between the advancing fallers whilst being subjected to further steaming. Finally they are advanced through the last zone D where they are dried, to ensure that the stretched fibres retain their stretched condition when the stretching forces are released. The dried fibres are then advanced to the discharge rollers 18.

FIGURES 3 and 4 illustrate a second form of stretching device. In this device, endless chains 22 and 23 are provided with elements 24 for gripping a sliver of wool. One of the chains 22 is provided with a plurality of stretching members 25 each terminating in a cam follower 26. The cam followers are moveable against an inclined cam surface 27 housed within the circuit of the chain 22 and the angle with which the cam is inclined towards the lower horizontal portion of the chain is adjustable. Each of the stretching members is supplied with a return spring 28 positioned between the chain 22 and a collar 29 mounted on the stretching member. Feed rollers 31 and take-01f rollers 32 are provided, together with longitudinal thrust strip 33 against which the lower ends of the gripper elements 24 on the chain 23 are brought into abutment. In a zone A, steam is applied to the fibres before commencement of the stretching operation. In the following zone B, both steam and stretching of the fibres takes place. Zones C and D are respectively zones where further steaming and then drying of the fibres is effected.

In operation, a sliver of wool fibres is fed into the device by means of the feed rollers 31. As the fibres enter between the belts 22 and 23 they are gripped by opposing pairs of elements 24 and are advanced through the Zone A where they are treated with steam. As the fibres are advanced they move into the zone B where stretching takes place in the presence of steam. In this zone the cam followers 26, which are following the contour of the cam surface 27, reach a part of the cam which inclines progressively towards the sliver. As a consequence, the end of each of the stretching members 25, which extend through apertures in the chain, is urged against the fibres and since the latter are gripped between opposing pairs of gripper elements 24 on either side of the stretching member the intervening length of fibres become stretched. When the fibers have passed through the zone B they are retained in their stretched position in their passage through zones C and D where they are subjected respectively to further steaming and drying.

The third embodiment, illustrated in FIGURES 5 and 6, comprises endless conveyor chains 35 and 36 which act as a carrier and are provided with gripper elements 37 for gripping a sliver of wool, passing through the device, to anchor the sliver across its width and at a number of positions along its length. The pairs of elements 37 are arranged into two interspersed sets, as described below, each set being arranged to be displaced laterally to the line of movement of the chains so that portions of the sliver anchored between adjacent gripper elements are extended. As seen generally in FIGURE 5, a sliver 14 is fed into the device by feed rollers 38 and leaves the device through take-off rollers 39, having passed through four zones A-D. In zone A, steam is applied to the sliver before commencement of the stretching operation. In zone 'B, steam is applied and stretching of the fibres takes place by lateral displacement of the sets of gripper elements. In zones C and D respectively, further steaming and then drying of the fibers is effected.

Details of the apparatus are shown in FIGURE 6. Each gripper element 37 is attached to a support of either a first form 41 or a second form 42. The supports 41 are of fixed length, and have rollers 43 directly mounted upon them at their ends remote from the elements 37. The supports 42 are of variable length, having portions '44, to which elements 37 are attached, slidable Within cylinders 45 against the action of springs 46. Rollers 47 are mounted on the cylinders 45.

The supports of the two forms 41 and 42 are arranged q alternately along the endless chains 35 and 36, a support 41 on one chain being opposite a support 42 on the other chain, and are slidable in a direction perpendicular to the chain. Alternate rollers 43 and 47 are arranged to roll respectively on endless cam plates 48 and 49 located generally along the line of travel of the chains 35 and 36. Within the zones B, C and D, the cam plate 48 diverges from the cam plate 49 so that the rollers 43 associated with the fixed length gripper supports 41 are diverted from their previous line of travel. The Wool sliver 14 is gripped between co-operating pairs of gripper elements 37, of each of which pairs one element is attached to a support 41 on one chain, and the other to a support 42 on the other chain. The lateral displacement of the supports 41 is accompanied by compression of the spring 46 of the opposite support 42, and the greater the displacement of the gripper elements 37, the greater the compression of the associated spring 46. In this way, the wool sliver is gripped more tightly between the gripper elements the greater their displacement. Firm gripping of the wool sliver 10 can thus be achieved at all times. The conformation of the gripping surfaces of the elements 37 may also be selected to ensure secure gripping.

In the apparatus shown, some gripping of the wool sliver 14 occurs between opposed gripper elements 37 when the sliver is first contacted by these members in the zone A. The pressure exerted by the gripper members then increases as lateral displacement takes place in the zone B. When the wool sliver has passed from the drying zone D, the gripper elements 37 separate and are returned on their respective endless chain conveyors 35 and 36 to the feed end of the conveyor run.

The amount of stretch applied to the sliver can be determined by the proportional extension in length which occurs between the adjacent opposed pairs of gripper elements 37, before and after their lateral displacement.

In a further alternative embodiment, the'steaming and drying zones are not located along the runof the conveyor system, but follow the conveyor. In this way the length of the conveyor with its associated stretching mechanism can be shortened. The stretched sliver is passed to a second, conventional conveyor which carries the sliver through the steam and drying zones. It is necessary in this case to ensure that the time interval between the end of the stretching operation and the commencement of the steam treatment is not so great as to result in unacceptable loss of stretch in the sliver. In one example of this modified process, a time interval of 10 seconds between stretching and steaming was found to give satisfactory stretch retention.

The following is an example of the production of bulked yarn from fibres treated in accordance, with the invention.

Samples of 64s Merino and Crossbred wool sliver were stretched in the apparatus illustrated in FIGS. 3 and 4.

Various blends of the stretched sliver with unstretched sliver were spun to R70/2 tex yarn (8.5 turns/in. Z twist in the single yarn and 5.5 turns/in. S twist in the folding). The following sequence of operations was used in the spinning:

Approximate Process Doublings Draft weight (g./m.)

Intersector gill 4 5 12. 5 D o. 4 5 10. Do 4 8. 0

Do 4 5 6. 4 Spindle gill 4 5 5 4. 6 Draw box-.. 2 6 1. 53 Rover 1 7 0.22 Spinner (ring)... 1 7 -0. 035

Yarn bulk Yarn diameter Was measured under a tension of 0.01 g./tex.

The length of yarn tested was weighed and the yarn packing factor calculated as:

Specific gravity of yarn 100 Packmg Factor Speoific gravity of fibre The specific gravity of wool was taken as 1.31.

Yarn bulk openness factor As a direct measure of bulk, a yarn openness factor is used, such that:

Yarn openness factor %=l00packing factor Yarn openness factor percent: 100-packing factor percent.

The yarn bulk is independent of the tex count and increases after relaxation. The unstretched control Merino yarns have a substantially higher bulk than the unstretched control Crossbred yarns both before and after relaxation.

In FIG. 7A, the openness factor percent is plotted against percentage of stretched fibre for Merino wool yarn. The curve U represents unrelaxed bulked yarn and the curve R similar yarn after relaxation. The control C is a relaxed yarn of 100% unstretched Merino fibre. In FIG. 7B, the corresponding information is plotted in respect of Crossbred wool yarn, the control C being a relaxed, 100% unstretched, crossbred yarn.

In the case of the bulked yarns, the bulk reaches a maximum at about 60% strecthed fibre in the blend, the bulk of both Merino and Crossbred yarns being similar in extent, but as the control Merino yarns have a much higher bulk than the control Crossbred yarns, the relative improvement in bulk as a result of the process is greater for Crossbred than for Merino yarns.

General conclusions Bulked yarns can be effectively produced by the blending of unstretched wool fibres with wool fibres stretched by the process of the present invention. The bulking effect is more pronounced in Crossbred than in Merino yarns due to the initial high bulk of Merino yarns.

The embodiments of the invention as described herein are capable of considerable modification. Thus the nature of the stretched fibre assembly can be varied according to the distance of separation of adjacent pairs of gripping members. When, for example, adjacent pairs of gripping members are spaced apart by a distance less than the average length of the fibre being treated, substantially all the fibres in the sliver will become stretched, in which case the resulting stretched material must usually be mixed with unstretched fibres prior to the manufacture of bulked textile materials. If, on the other hand, the pairs of gripping members are more widely spaced, only a proportion of the fibres become stretched and consequently the subsequent mixing operation may not be necessary. The degree of separation of pairs of gripping members can be varied in different ways according to the design of stretching device employed. Thus the number of fallers in the device illustrated in FIGS. 1 and 2 can be varied, and the variable pitch screw conveyors can be exchanged for others of different pitch. In the device illustrated in FIGS. 3 and 4 the number either of gripping members or of stretching members employed, or of both, can be varied. With both forms of device variation of the speed 'With which fibres are feed into the device has an effect similar to that which can be obtained if the spacing of the gripping members and the stretching members is varied. Thus slight over-running has an effect which is very similar to that which is obtained by spacing the fallers or stretching members more widely apart.

I claim:

1. A process of stretching an assembly of textile fibers,

including the steps of:

(a) clamping an assembly of textile fibers across its width at a plurality of points, said points being longitudinally spaced along the assembly,

(b) successive pairs of said clamping points each defining a station, to thereby define a plurality of stations,

(0) progressively increasing the length of the fibers within each station, said increase being different for at least two adjacent stations.

2. The process of claim 1 wherein,

(a) step 1(c) is performed by laterally displacing the fibers in the stations, the clamping points remaining stationery with respect to said lateral displacement.

3. The process of claim 1 wherein,

(a) step 1(c) is performed by moving the clamping points of the stations away from each other, in a direction parallel to the textile assembly.

4. The process of claim 1 wherein,

(a) step l-(c) is performed by moving adjacent clamping points of the stations laterally, in opposite directions, from the textile assembly.

5. The process of any of claims 1, 2, 3 or 4, wherein,

(a) the step of increasing the length of the fibers is performed concurrently with a process for setting the fiber assembly undergoing distension.

6. A device for stretching textile fibers including,

(a) a conveyor provided with gripping members along its length, the gripping members adapted to anchor an assembly of textile fibers,

(b) successive pairs of gripping members each defining a station,

(0) means for increasing the length of textile fibers in at least two successive stations by differing amounts.

7. The device of claim 6 wherein,

(a) said 6(c) means is defined by stretching members laterally displaceable with respect to th length of the conveyor, said members adapted to touch and distend fibers gripped in the stations.

8. The device of claim 6 wherein,

(a) said 6(c) means is defined by means for moving adjacent gripping members of each station laterally, in opposite directions, from the length of the conveyor.

9. The device of claim 6 wherein,

(a) said 6(c) means is defined by means for moving the gripping members of each station away from each other, along the length of the conveyor.

10. The device of any of claims 6, 7, 8, or 9,

(a) including means positioned along said conveyor for setting the fibers of a fiber assembly.

11. The device of claim 6 wherein,

(a) said conveyor is defined by a pair of endless chains each provided with gripper elements in pairs, to define the stations, I

(b) at least one of said chains being provided with a plurality of stretching members for laterally displacing portions of the fiber assembly gripped in the stations.

12. The device of claim 6 wherein,

(a) said conveyor comprises a pair of parallel variable pitch screw conveyors, including two sets of fallers respectively cooperating with the conveyors for advancement thereby from a feed end to a discharge end of the device and means for returning the fallers to the feed end, the fallers arranged to cooperate in pairs in gripping and assembly of textile fibers at successive positions of anchorage,

(b) said screw conveyors adapted to increase the separation between adjacent fallers as the conveyors are advanced thereby.

13. The device of claim 6 wherein,

(a) said conveyor isdefined by a pair of parallel endless chains respectively provided with gripper elements cooperating in pairs, each pair defining a station to grip an assembly of textile fibers,

(b) the pairs of gripper elements being arranged in sets with the pairs of elements of a first set being interposed between the pairs of elements of a second set,

(c) said 6(c) means defined by means for displacing the fisrt set of said gripper elements laterally with respect to the second set of gripper elements.

References Cited UNITED STATES PATENTS 2,394,165 2/ 1946 Getaz 19-66 2,636,250 4/1953 Hemmi. 3,341,899 9/ 1967 Marriner 1966 FOREIGN PATENTS 75,927 7/ 1894 Germany.

LOUIS K. RIMRODT, Primary Examiner U.S. Cl. X.R. 28-1, 71.3, 72 

